Humidifier



May 12, 1925.

B; M. MILLS HUMIDIFIER Filed March 15 1924 MI! m.

fiivezvtbr dt iowiiy Patented May 12, 1925.

UNI-TED STATES 1,537,650 PATENTVOFFICE. Q

IBERTRAM M. MILLS, OF PAWTUCKET, RHODE ISLAND.

HUMIDIFIER.

Application filed larch 13, 1924. Serial N0. 698,884.

To all whom it may concern:

Be it known that I, BERTRAM M. MILLS, a citizen of the United States of America, and resident of Pawtucket, in the county of Pawtucket and State of Rhode Island, have invented new and useful Improvements in Humidifiers, of which the following is a specification.

This invention relates to humidifiers or atomizing devices employed for moistening the air in rooms or apartments, and more particularly to means for regulating such apparatus.

Humidifiers of portable type designed for use in houses, ofiices, etc. are necessarily of small size and compact construction, and to meet the demands of the trade must be provided with motors of universal series wound type adapted to operate at high speed under either direct or alternating electric current. I

In one very efiicient type of humidifier the water is atomized by means of a substantially horizontal disk rotating at high speed, the Water being contained in a shallow receptacle and fed to the disk by means of a conical boss depending into the liquid from the center of the disk, the water creeping up the sides of the boss under centrifugal action. While this type of humidifier is in general very satisfactory, it is observed that as the water level in the container falls, the series motor tends to speed-up, due to the lessened resistance encountered by the conical boss. Such undue speeding of the motor-is undesirable for several reasons, among which may be mentioned the nonuniform evolution of vapor from the device and the unpleasant noise or hum occasioned by the imperfectly balanced rotat-' ing parts running at excessive speed.

The object of the present invention is in general to improve humidifiers of the type referred to and more particularly to provide such humidifiers with means tendingto maintain a uniform speed of the motor .and other rotating parts regardless of the depth of liquid in the container or reser- One .mode of attaining the above object which has been chosen forspecific illustration herein consists in providing the lower portion of the depending conical feed boss with one or more grooves, preferably spiral or helical, in its outer surface. These grooves are disposed at the lower end of invention;

the conical boss and preferably become gradually shallower toward their upper ends. The provision of these grooves re sults in the maintenance of a substantially uniform load upon the motor irrespective of the position of the water level in the container, thus providing a substantially constant speed of operation with elimination of noise and the attainment of uniformity in vapor output.

While the exact reason for this action which is observed to take lace is not thoroughly understood, it is elieved that when the grooves in the conical boss are completely submerged they present comparatively little resistance to rotation, but as the water level falls and the grooves are gradually exposed they encounter resistance to rotation at the surface level of the water due perhaps in part to the greater cohesion of the molecules of liquid at the surface, commonly referred to as surface tension and in partto the formation of Waves or ripples upon the fluid surface, in either case requiring the expenditure of additional energy. Whatever the ,true theory of operation, the grooves herein described and illustrated constitute an exceedingly simple and eflicient means for attaining the desired object, but it is contemplated that other and equivalent means producing the same or analogous efi'ects .fall within the purview of the invention.

In the accompanying drawings one specific embodiment of the invention has been chosen by way of example for illustration, and in the drawings:

Fig. 1 is a vertical diametral' section through. a humidifier embodying the present Fig. 2 is a fragmentary side elevation of the lower end of the conical feed boss of the atomizer disk; and

Fig. 3 is a horizontal section on the line 33 of Fig. l. a

The present invention is illustrated as sin bodied in a humidifier ofthe general type disclosed in the application of Bertram M. Mills, Serialv No. 670,257, filed October 23, 1923 to which application reference may be had for a more detailed disclosure of the operative parts of the humidifier proper.

In the drawings, the numeral 1 indicates av shallow receptacle for the water or other fluid .to be atomized. This receptacle is provided with a flaring rim 2 having an inwardly directed flange 3 constituting a support for a cover 4; whoselateral edges are flanged downwardly and rest upon the supporting member 3. The flanged depending edge of the cover 4 is slotted and bent to provide a series of atomizing vanes 9.

The cover t forms a convenient support for 'a base member 5 upon which an electric motor 6 is supported. This motor is preferably of universal type adapted alternatively to operate muler-dircclor alternating electric current. Such motor are usually series wound. at least in the sizes proper for use in portable humidifiers. Such series wound motors are well suited to use in a humidifier device of small size by reason of the high speeds which may thereby be obtained, but as the speed of such a motor varies inversely with the load it necessarily follows that if the load is unduly decreased the motor may race.

The shaft 7 of the motor extends downwardly through an opening in the plate l and the atomizing disk 8 is secured to the lower end of the shaft. This disk may be of any usual type. preferablyhaving a substantially smooth lower surface from the center ot which a conical boss 9 depends. VVlnle the term conical is employed as a con-' venient. mode of designating the general shape of this boss it is to be understood that the term is used in a generic sense as including any device providing an upwardly and outwardly divergent peripheral surface, whether exterior or interior, and whether substantially straight or curved.

The peripheral surface of the boss 9 is provided with one or more grooves extending upwardly from its lower end. As here shown three such grooves are provided, andthese grooves extend helically or spirally about the axis of the boss. Preferably, although not necessarily, the grooves are deepest at their lower extremities, becoming gradually shallower toward their upper ends 12.

I In practice, it is found that the best results are obtained by terminating these grooves substantially at the mean waten level although the exact extent of the grooves maybe varied in accordance with their shape, the angle of convergence of the conical boss, and various other factors which will vary with the individual application of the invention; \Vhile it is preferred to employ the grooves here shown, it is contemplated that similar results may be obtained by the-use of other means associated with the conical boss adapted to maintain a substantially uniform resistance to turning of the bossirrespective of the water level.

In operation, the motor 6 rapidly rotates the disk 8 and its boss 9 with theresult that centrifugal action causes the water to creep up the peripheral surface of the boss onto the lower surface of the disk 8 upon which it is'drawn out into an exceedingly tenuous film and projected with. great force against the vanes 5 so that it is completely broken up. \Vhen the receptacle 1 is substantially full the grooves 10 are entirely submerged andlapparently offer but slight added .rc sistance to the rotation of the conical boss 9 so that the speed of the device is but little reduced from that normally attained with an ungroovcd boss and with the receptacle full. As the water level in the receptacle falls, the upper shallow ends of the grooves are first uncovered, thereby producing an increased resistance to rotation substantially sufficient to compensate for the decreased area of the boss remaining immersed in the water. As the water level continues to fall, the deeper portions of the grooves 10 are gradually exposed, such deeper portions providing a further increased resistance to turnmg, and this action progresses until the water level has fallen substantially to the resistance or load irrespective of the position of the water level in the container and thus the'speed of the rotating parts does not vary substantially. The vapor output'is thus uniform throughout the use of the device while all undesirable noise due to racing of the motor .is eliminated.

I claim:

1. A portable humidifier comprising a fluid receptacle,;an atomi'zingelement, means for feeding'fluid from the receptacle to the atomizing element, means for rotating the atoinizing element, and means tending to vary the resistance of the atomizing element to rotation in inverse ratio tothe height of the water level in the container. I

2. A humidifier comprising a fluid receptacle, a rotary atomizing disk, a conical feed member depending from the center of the disk into the receptacle for feeding water from the latter to the disk, means for rotating the disk, and means associated with the conical member for maintaining a substantially constant resistance to rotation of the latter as the fluid level varies in the con- 1 tainer.

'3. A portable humidifier comprising a fluid receptacle, a rotary atomizing disk, a conical boss depending from the central part of the disk into'fluid in the receptacle, an

electric motor for rotating the disk and its boss, and means operative as the water level in the container descends to provide an increasing resistance to rotation directly proportional to the normal decrease in resistance due to the diminishing area of the boss immersed in the fluid.

4. A humidifier comprising a fluid receptacle, an atomizing element, a rotary conical feed member dipping into the fluid in the receptacle and adapted to feed water to the lower end of the boss 10. In this way the m'otor encounters a substantially uniform atomizing element by centrifugal action, and an electric motor for rotating said conical feed member, said feed member having a groove in its peripheral surface extending upwardly from its lower end.

5'. A humidifier comprising a fluid receptacle, a rotary atomizing disk, a conical feed boss dep ndingfrom the center of the disk into the uid in the receptacle, and an electric motor for driving the disk and its boss; the boss having a groove in its peripheral surface extending upwardly from its lower end, the groove being of dlminishi'ng depth from its lower substantially to its upper extremity. p 6. fl humidifier comprising. a. fluid receptacle, a rotary atoinizin disk provided with a conical depending eed boss depending Signed by me at Pawtucket, Rhoda lslaiid;

this 7th day of March, 1924. i

BERTRAM M. MILLS. 

